Should I call 911 when my next door neighbor has her screaming bouts?

I hear her throwing things, hitting walls, screaming for help. The bouts can span hours, maybe most of the day. A few days ago she even screamed, "HELP! CALL 911!" Eventually we called, EMS responded and transported her away. She was back home again by the next day and now, a couple days later, she's screaming help again.

My hesitation is because:
1. When screaming for help some years ago, my parents ran to her aid only to have her scream at them, tell them to leave and accuse them of harming her. When they left her home she took her wheelchair onto our lawn, throwing things, and pounding against our walls while screaming, "YOU DIDN'T HELP ME!" plus calling them some profanities.
2. She has had screaming spells about once or twice a week on average (there are months when it's every day and then there are those when I hardly hear her) for at least 6 years now. I would hate to ignore a screaming fit if she is in real trouble, but I can't help becoming desensitized.

She has had a number of really nice live-in caretakers (private hire, non-medical workers) over the years that I really liked, but behind doors (my window is across from hers by only about 7 feet so I hear a lot without meaning to) I hear her screaming at them and hitting walls. It sounds violent and her caretakers all pack their things and leave after a short while.

I don't know her diagnosis. Her cognitive function oscillates. On a rare occasion she will be alert enough to tell me about her past in a way that is temporally logical, with appropriate responses to my contributions and questions. But the vast majority of the time her conversation is identical day after day: "I love your dog. My dog isn't as great. I used to have a great dog." And then sometimes the past 20 years just vanish: "Are you the little girl that lived next to me?" But on her really bad days she says nothing, frowns, and unearths flowers from peoples' yards even while they watch, placing them in her lap and gunning the wheelchair home, where she has her caretaker plant them for her.

She had no children and I understand that her relatives, if any remain, live on the other side of the country. I am not sure if her caretaker is present when she screams for help, as I haven't seen the caretaker in sometime - perhaps she moved out.

I'm terrified to talk to my neighbor about her mental state and her caretakers thus far have only spoken broken English while I only speak broken Spanish. Also, her caretakers have all gone from friendly to recluse during their stay; they stop smiling, stop saying hi, stop making eye contact.

I think that my neighbor might need a more intensively supportive environment. Her behavior has burned nearly all of her bridges in the neighborhood and now I think I might be alone in worrying about her. I don't want to call 911 every time she has a fit, but I feel terrible always doing nothing.